The present invention relates to a video information recording and reproducing apparatus for recording and reproducing chiefly video information.
In recent years, disk drives respectively using optical disk and magnetic disks have been developed to have a larger capacity of storage and operate at higher speed, and image compression technology has also been remarkably advanced. A magnetooptical disk drive using a 130 mm diameter disk of which the one-side storage capacity is 1 GB or more, and a magnetic disk drive using 90-mm diameter disks of several GBs per disk, are practically used. In addition, a first-generation rewritable digital video disk (hereinafter, abbreviated DVD-RAM) will be produced in the near future, which is able to record information of 2.6 GB on one side of a phase change optical disk with a diameter of 120 mm. These optical-disk and magnetic-disk drives are capable of transferring data at a high rate of several tens of Mbps.
As to the image compression technology, MPEG (Moving Picture Experts Group) is established as an international standard for moving picture compression. In MPEG 1 substantially equivalent to the picture quality of VHS of VTR, the data transfer rate is 1.5 Mbps, and a capacity of about 600 MB will be needed to store moving pictures of 60 minutes. In MPEG 2, a data transfer rate of about 4 to 6 Mbps is necessary to achieve the picture quality of the present TV received picture quality or above, and the capacity for moving pictures of 60 minutes is about 1.8 to 2.7 GB. Thus, with the development of the above disk drives using optical and magnetic disks and the advancement of the image compression technology, it has become possible for the moving picture information which needs a high capacity of storage and a high rate of data transfer to be treated by the disk drives. Consequently, the industry is now seriously considering the application of these disk drives not only to a large-scale video server but also to a home video recording and reproducing apparatus.
There is now a video tape recorder (hereinafter, abbreviated VTR) as the home video recording and reproducing apparatus, which is now very popular. The conventional apparatus has a function of recording and reproducing one-channel video, and a search function such as programmed recording function. Since VTR uses a tape, or a sequential memory as a recording medium, it can record one program or reproduce one recorded program at the same time. The programmed recording function is to record a desired program by previously inputting the channel number, start time and end time into the VTR from a remote controller which the user handles. The VISS as the present search function of the VTR is to find the beginning of a recorded program on the basis of an index signal recorded on the tape at the time of starting to record.
Japanese Patent Laid-open Gazette 5-303873 describes that an arbitrarily recorded image portion can be reproduced in real time from a plurality of random-accessible image recorded portions without interrupting the recording.
However, use of only the above function to find the beginning cannot realize true free time-shift viewing.
In the gazette, when the user tries to view a recorded program at an arbitrary time under the condition that a certain program is being recorded on the VTR (for example, programmed recording),it is necessary to stop the recording operation or wait until it ends. In other words, the present VTR cannot realize free time-shift viewing in which the user can view a desired program at an arbitrary time.
In addition, the programmed recording operation in the gazette requires the user to input channel number, starting time, and end time into the VTR as describe above, and is thus very troublesome. Recently, a simplified programmed recording function such as G code is used, but it is not basically improved in its operation. Thus, the programmed recording function of the VTR cannot be widely used.
Moreover, since the VISS as the search function of the VTR is to only find the beginning as described above, the user cannot instantly know the contents of the recording on the tape, and thus must search the programs by finding the beginning of each program. Therefore, since it takes a much longer time to search a plurality of tapes, this search function is not practical.